1. Technical Field of the Invention
The present invention relates to an optical disc apparatus and particularly to a drive technique for raising and lowering a turntable to chuck an optical disc.
2. Description of the Related Art
Examples of techniques related to the present invention include those disclosed in Japanese Patent Laid-open No. 2002-352498 and Japanese Utility Model Laid-open No. 7-41783. Japanese Patent Laid-open 2002-352498 discloses a disc drive wherein a traverse (unit mechanism portion) is raised and lowered by a first cam mechanism formed on a surface of a main slider and a second cam mechanism mounted on a surface of a sub-slider. Japanese Utility Model Laid-open No. 7-41783 discloses a disc drive including a cylindrical cam gear having a cylindrical cam and a lift lever member which is pivotally moved by the cylindrical cam to move the unit (unit mechanism portion) upward.
However, according to the technique described in Japanese Patent Laid-open No. 2002-352498, since the cam mechanism is formed on the slider surface, the size of the portion for raising or lowering the traverse is liable to become large. Further, it is presumed that the technique described in Japanese Utility Model Laid-open No. 7-41783 is for application to an optical disc apparatus (e.g., a half-height type) having a tray and having an allowable thickness range of, e.g., about 25×10−3 mm or more. It is difficult to apply this technique to, for example, a thin slot-in type (the type in which an optical disc is pulled into the body of the optical disc apparatus directly without using a tray). Moreover, the cylindrical cam is configured to pivot in interlock with a tray pulling-in operation into the body of the optical disc apparatus during disc loading or a tray pulling-out operation to the exterior of the optical disc apparatus during disc unloading. During its pivoting motion within one full turn, it responds to the tray pulling-in or -out operation and causes the unit (unit mechanism portion) to move upward or downward. Consequently, a large cylindrical cam diameter is needed and the whole of the cylindrical cam gear becomes large-sized. Besides, the cylindrical cam gear is disposed in an area outside the outer periphery of the optical disc on a disc inlet side and thus also from this point a planar size of the optical disc apparatus is liable to increase. Further, also on the lift lever member side which engages a cam groove of the cylindrical cam, a cam follower is connected to the lift lever member and a spherical portion is formed at the tip of the cam follower and is brought into engagement with the cam groove in an extended state of the cam follower toward a side face of the cylindrical cam. Thus, the lift lever member side is also required to have a large size.
The present invention has been accomplished in view of the above-mentioned situation of the conventional techniques and the problem to be solved by-the invention is how to construct a raising/lowering mechanism for the unit mechanism portion so as to reduce the size and thickness of an optical disc apparatus.
It is an object of the present invention to solve the above-mentioned problem and provide a technique that permits a further reduction in size and thickness of an optical disc apparatus.